Follow the blog here!

Top 25 MLB Players Under 25 For 2018

This is the first installment of what I hope will become an annual preseason series: “Top 25 MLB Players Under 25.” The premise and methodology are both fairly straightforward: I will consider a player’s body of work in the majors, the minors (to a lesser extent), his pedigree, and his potential for growth. There are a plethora of young talented players in baseball but not all of them are well-known, so I’ll look to highlight the best of those youngsters in this series. In order to be eligible for the list, a player has to have made at least one appearance in the big leagues (so no minors-only players; apologies to Vlad Guerrero Jr. and Ronald Acuna). I will be evaluating players on a combination of their projected upside and how they have already performed in the major leagues. After each player, I will list their position, team, and age on Opening Day 2018.

Just Missed

There were 15 guys that I picked out that just missed the top-25 cut for a plethora of reasons. I’ve listed them alphabetically below according to position.

The #25 spot was splitting hairs between Eduardo and a couple of other guys. I can’t say I have been overwhelmingly impressed with Rodriguez’s work so far, and due to injury he hasn’t pitched a full season since coming to the majors. He is also slated to begin the year on the DL.

In spite of all this, Rodriguez is just 24 years old with room for improvement, and 2017 was his best season in terms of fWAR, so he’s trending in the right direction. His 4.23 career ERA is a little unsightly for one of the “top 25 under 25,” but he’s been a solid contributor at the MLB level for the past three seasons and consistency is to be rewarded.

Everyone who reads my blog or talks to me about baseball is well aware that I am a big Jesse Winker fan. He is my pick for NL Rookie of the Year this season. Despite other “25 under 25” lists not including Winker in the top 25, I felt I needed to shout him out due to his good stint in the majors last year, his pedigree, and his solid production in the minors. His .298/.398/.449 minor league triple-slash is not gaudy, but it is very good. In his short time in the majors, though Winker was a flat-out stud, triple-slashing .298/.375/.529 with 7 HR in 137 PA. He also walked at a 10.9% clip as a 23-year-old, which is very impressive. Winker does not get enough love and he’s going to show everyone why he deserves to be on this list heading into 2018.

I’m not the biggest Mazara fan, but as I said consistency is to be rewarded. Mazara owns a .259/.322/.421 over 1184 MLB plate appearances and he doesn’t turn 23 until the end of April. Mazara has consistently been one of the youngest players at each level and he has proven his ability to hang with older and tougher competition. The Rangers have rewarded him with aggressive assignments and promotions, and he captured a full-time role during the 2016 season. Mazara is looking to post his third consecutive 20-HR season in 2018 and continue to improve upon his plate discipline metrics.

It’s always tough to evaluate relief pitchers since they simply do not produce as much of a sample size as batters and starters. Diaz, though, has been one of the best relievers in baseball since making his big league debut. Here’s a comprehensive list of pitchers with a better K/9 than Edwin Diaz since his debut in June of 2016: Craig Kimbrel, Kenley Jansen, Dellin Betances, Andrew Miller, and Corey Knebel. Strikeouts are not everything; Diaz is also the proud owner of a career 3.06 ERA, 52 saves, and 75 games finished. The fireballing righty is just 24 years old, so there is still room for improvement despite his excellent performance so far.

Happ was lauded as a top-50 prospect in all of baseball entering 2017 but does not have an everyday role guaranteed for 2018. After he triple-slashed .253/.328/.514 with 25 HR in 115 games in 2017, it will be hard for the Cubs not to find ABs for the youngster, but the Cubs have a lot of talent on their roster. Happ will be competing with Albert Almora, Javier Baez, Albert Almora, and (to a lesser extent) Ben Zobrist for playing time. He would certainly be higher on this list if he had more of a track record of success in the major leagues, but because the Cubs are loaded with great players, they can afford to rest the young lefty whenever they feel necessary.

In a lot of ways, DeJong and the aforementioned Ian Happ are very different. DeJong (pronounced dih-YOUNG) burst onto the scene in a big way in 2017. A relatively unheralded prospect, he did not appear in the Cardinals organizational top-10 prospects (according to MLB) during his minor league tenure, though some outlets placed him near the bottom of the top-10. He then made everyone look silly for not giving him more love by triple-slashing .285/.325/.532 with 25 HR in 108 games. DeJong is the typical Cards prospect: unheralded coming out of the minor leagues and then simply very productive but not all that flashy once reaching the major leagues. The Cards have so much faith in DeJong that they traded away Aledmys Diaz, who started at short for St. Louis on Opening Day in 2017. DeJong is the shortstop of the future for the Cardinals.

Devers made a name for himself in the major leagues by hitting a game-tying HR off a 103 MPH Aroldis Chapman fastball with one out in the top of the ninth in August of 2017. Prior to that, though, he quietly mashed in the minor leagues and was ranked as the top 3B prospect entering 2017. His minor league triple-slash line of .296/.354/.482 is nothing short of impressive, especially considering that he has been one of the youngest players at every level he has played. He was the youngest player in the AL in 2017 (20 years old) and will not celebrate his 22nd birthday until October of 2018. Devers is a star in the making and should occupy the hot corner for the Red Sox for at least the next half-decade.

It’s possible that I am ranking Moncada too high because I have had him on my fantasy team since he signed with the Red Sox in March of 2015. Then again, possibly not. Moncada struggled in a brief stint with the Red Sox in 2016 and was shipped to the White Sox in the Chris Sale trade the following offseason. He improved his numbers a little bit after debuting in Chicago but didn’t really get going until September of last season. Prior to September last season, Moncada posted an abysmal triple-slashed of .188/.328/.356 with a 36.1% strikeout rate and just 3 HR in 122 PA. He went on the disabled list at the end of August and shortly after returning showed everyone why he was such a highly-touted prospect. He triple-slashed .276/.349/.469 with 5 HR, an improved 27.5% strikeout rate (which still needs work), and a 9.2% walk rate in September. The 22-year-old Moncada is set to open 2018 as the White Sox leadoff hitter and could shoot up this list prior to next season if he continues his September performance from 2017.

I’m just as surprised as you that Buxton is just 24 years old, because it feels like he’s been around for a handful of seasons. He was Minnesota’s full-time starting CF in 2018 and did not disappoint, though he was not stellar either. His defense is elite (the gap between his 25 Outs Above Average and second place Ender Inciarte’s 19 is larger than the gap between Inciarte’s OAA and fifth-place Lorenzo Cain’s 15 OAA) and his bat finally came around a little bit in 2017; he triple-slashed a not-bad-not-great .253/.314/.413 with 16 HR and 29 SB (and just 1 caught stealing! That’s a 96.7% success rate!). His plate discipline could use some work (29.4% strikeout rate and 7.4% walk rate in 2017), but all-in-all, things are looking up for the young Twins outfielder.

Joey Gallo is like Adam Dunn on steroids. Not literal steroids, but he’s basically the second coming of Dunn. Adam Dunn is considered the original three true outcomes (walk, strikeout, home run) player due to the fact that 49.9% of his career 8328 PA ended in a walk, strikeout, or home run. If you think 49.9% of plate appearance resulting in one of the three true outcomes is a high number, you haven’t seen Gallo’s percentage: 60.6%. Seriously. And, unfortunately for Gallo and Rangers fans, the strikeouts are a whole lot more likely than the other two.

With that being said, Gallo triple-slashed .209/.333/.537 with 41 HR in 2017 which is even more impressive once you see his 36.8% strikeout rate. He also hits the ball ridiculously hard; his 93.1 average exit velocity in 2017 was the second-highest in all of baseball. Gallo is going to be a perennial 50-HR threat if he can get his contact rate up at least a little bit, and if he does, he’ll likely become one of the best players in all of baseball.

Sano and Gallo are very similar. Sano’s 92.4 MPH average exit velocity ranked 4th, just behind Gallo. Whereas 60.6% of Gallo’s PA end in one of the three true outcomes, just 53.5% of Sano’s do. Perhaps “just” isn’t the right word there; 53.5% of PA ending in one of the three true outcomes is a pretty big number. Over Sano’s 313 MLB games, he has posted a triple-slash line of .254/.348/.496 to go along with 71 HR and a 124 wRC+. His 35.8% strikeout rate could use some work, but it is mitigated by his 12.3% walk rate and the fact that when he does make contact, he hits the ball hard. The fact that Sano is just the second of three Twins on this list is a great sign for that squad, and Sano will be anchoring the Twins lineup for the foreseeable future.

Berrios was one of the most highly-touted pitching prospects in all of baseball leading up to his debut in 2016. He then posted a comical 8.02 ERA in 58.1 innings pitched his rookie year and had to begin the 2017 season at AAA. Once he returned to the major leagues, he drastically improved his numbers. His 2017 season saw him go 14-8 with a 3.89 ERA, 1.229 WHIP, 8.6 K/9, and 3.84 FIP. He improved across the board in 2017 but still has not reached the elite level that he was expected to as a prospect. Fortunately for the young righty, at just 23 years old, there is plenty of time to improve and develop into the truly dominant starter he was expected to become.

This will be Osuna’s fourth season in the league and he does not turn 24 until 2019. In his three seasons as a big leaguer, he has been nothing short of dominant, amassing a 2.86 ERA, 0.905 WHIP, 10.4 K/9 (that has improved every season), and 95 saves. Not only is Osuna one of the best closers in baseball, but he has a legitimate shot at breaking Mariano’s save record because he got started so early. He would likely have to pitch until he is at least 40 to break it, but it’s very possible. Osuna has been one of the best relievers in the league since entering in 2015 and at the young age of 23, shows no signs of slowing down.

Olson made his MLB debut during a 2016 cup of coffee and was absolutely terrible (52 wRC+), so it came as a shock to nearly everyone when he hit .259/.352/.651 with 24 HR in 59 games after being called up in 2017. He also had the seventh-highest rate of barrels per plate appearance behind names like Aaron Judge, Giancarlo Stanton, and Joey Gallo, just to name a few. After his obscene performance last year, Olson is penciled in as the Opening Day first baseman for the Athletics and should remain there until Billy Beane decides to trade him, as the GM tends to do with most Athletics stars. Until then, Athletics fans should enjoy watching one of the young budding sluggers taking the league by storm.

“But Max,” you say, “Chapman made his debut last year and hit .234 in 326 PA. Why is he so high?” Because he plays incredible defense, and behind that average sits a 9.8% walk rate and 36.0% hard-hit rate that was almost 5% above league average in 2017. I have always been a sucker for defensive standouts; Kevin Kiermaier, Andrelton Simmons, and Billy Hamilton are among my favorite players. Chapman is next in the line of players who will not get enough love because they make their biggest contributions on defense. For reference, Chapman compiled 2.7 fWAR in just 84 games in 2017, which would make him a 5+ WAR player over a full season. And if you are a sucker for defensive highlights like I am, I hope you’ll enjoy this video as much as I did.

I want to give a quick shoutout to my brother, Sam, because he is one of Bellinger’s biggest supporters. Maybe he’ll forgive me for ranking Bellinger at the back of the top 10. In 2017, Bellinger was one of the best overall players in baseball; triple-slashing .267/.352/.581 with 39 homers will do that. However, he did go down on strikes 26.6% of the time and his defense wasn’t exactly spectacular. I have no doubt he will be higher on this list next year, but because of his strikeout numbers and his average defense, I don’t think I can slot him in any higher than this for 2018.

First off, I just want to say that Lance McCullers is a great Twitter follow, so go throw him a follow if you have not already. Now that you’ve done that, let me tell you about how dominant McCullers has been since coming up to the major leagues. In parts of three seasons, the young righty has put together a 3.60 ERA, 3.14 FIP, 10.2 K/9, and 7.8 fWAR. The only problem is that he’s pitched just 325.1 innings over those three seasons due to injuries. If McCullers can remain healthy for a full season he will unquestionably be one of the best pitchers in all of baseball, but that’s a big if. The best ability is availability, and until he demonstrates that there’s no logical reason to move him up this list.

Benintendi gave Red Sox fans a taste of what he is capable of by posting a .295/.359/.476 triple-slash with 2 HR in 34 games at the end of 2016. In 2017 he became the everyday left fielder for the Red Sox and triple-slashed .271/.352/.424 with 20 HR, 20 steals, and a 10.6% walk rate. He tied for 27th in the big leagues last season among qualified hitters with a 0.63 walk-to-strikeout ratio. In addition to being one of the most eligible bachelors in the United States, the 23-year-old is in the conversation for best hair of any major leaguer. Oh, and he’s a pretty good ballplayer, too.

Bregman has quietly been one of the best 3B in baseball since being called up to the big leagues in 2016. His career triple-slash of .279/.342/.476 has justified the Astros selecting him with the second pick in the 2015 draft. He should threaten 20/20 every season for the next decade (he had 19 HR and 17 steals in 2017), and adding him to an infield that features Jose Altuve and Carlos Correa is flat-out terrifying. Bregman doesn’t do anything particularly flashy, but quiet consistency is even better than flashiness.

Speaking of flashiness, let’s take a trip to our nation’s capital. Turner has yet to play in a full MLB season due to injury, but those injuries have mostly been freak accidents, so expect him to put together a full year in 2018. The young shortstop owns a career .304/.348/.491 triple-slash line in the majors with 25 HR and 81 steals (seriously) just 198 games. If he plays a full season in 2018, I fully expect him to lead baseball in stolen bases just because he can actually hit the ball and Billy Hamilton can’t. Turner is going to be a stud for years to come but the injuries have prevented me from elevating him on this list.

After a decent 2015 and a bad 2016, Severino was simply spectacular in 2017. The young righty earned third place in AL Cy Young voting thanks to a 2.98 ERA, 1.040 WHIP, 4.51 K/BB ratio, and 152 ERA+. The best part about Severino’s 2017 season is that he threw 193.1 innings, proving his ability to be a workhorse. His 6’2″, 215 frame also suggests that he will be able to handle 200+ inning workloads for the next few seasons. Severino will only get better from here on out, so expect him to sit on or near the top of Cy Young ballots for the next decade.

Maybe it’s something about people with first names starting in “A” that makes them have great hair. And while I think I have to give Benintendi the edge on hair, Nola has certainly been the better player to this point in his career, and gets almost no love. Through three seasons (356.2 innings, 60 starts), Nola has put together a 3.94 ERA, 1.24 WHIP, 9.41 K/9, and 2.45 BB/9. He’s a bonafide ace, and if he is able to throw 200+ innings in 2018, he should be in the conversation for Cy Young.

Corey Seager is another rock of consistency, which is incredibly impressive considering his age. He’s already compiled one five-WAR and one seven-WAR season (measured in fWAR) and he’s only 23 years old. He owns a career triple-slash of .305/.374/.502 in the big leagues which, when coupled with his 9.6% walk rate, is nothing short of elite. Seager has not even hit his final form yet, which is the best part of all his success. Unfortunately for him, the two names ahead of him have been even better, but Seager and the two gentlemen in front of him comprise the top-tier under 25 players in all of baseball right now.

“Mr. Smile” has had a lot to be happy about since being promoted to the big leagues in 2015. Frankie is the proud owner of a .293/.349/.474 triple-slash line, 60 HR, and 46 stolen bases in three seasons. He has also finished in the top ten in the AL in MVP voting back-to-back seasons and opens 2018 as just 24 years of age, which is old relative to other guys on this list, is still extremely young in the scope of the big leagues. Lindor is a tried-and-true stud and aside from being one of the best players under 25, is also one of the best players in baseball in general.

It seems fitting that the top player on the list is one of the top players on the top team in baseball. Correa debuted in the big leagues as a 20-year-old and hasn’t stopped raking since then. In three seasons, he has triple-slashed .288/.366/.498 with 66 HR, 29 SB, and a 10.7% walk rate. His career wRC+ is 135. For reference, all the other players on this list who have played at least 81 games in a season (half the year) have combined for just two seasons of 135 or more wRC+ (Bellinger’s 2017 and Seager’s 2016). Correa is one of the elite talents in Major League Baseball right now and deserves to be treated as such, which is why he tops this list.

Like what you read? Make sure to click on the main menu (in the top right corner) and enter your email in the “follow” box. It’s free!

Max Brill is a junior at the University of Michigan — Stephen M. Ross School of Business.
Max has worked for the New York Mets as a Player Development Intern and the Yarmouth-Dennis Red Sox of the Cape Cod Baseball League as a beat writer. He is also an analyst for the Michigan Baseball Team and a Communications and PR intern for Michigan Athletics. Max was born and raised in the greatest city in the world, New York City, and is a die-hard Mets fan. He is the creator of Musings of a Baseball Addict.
How to contact Max:
Email: musingsofabaseballaddict@gmail.com
Twitter: @metsfanmax